18.1. ColorSliders.setModel(): Display a new color
model

It is not necessary to display the name of the currently
selected color model here. The user can look at the ModelSelector widget to find that out, or they can look
at the labels displayed on the parameter sliders.

The primary work of this method, then, is to tell the
ParamSlider widgets to change their labels
to those of the parameters of the new models. Once they
are relabeled, we call Section 18.2, “ColorSliders.setColor(): Change the
displayed color” with the current
color, which will tell the parameter sliders to redisplay
that color using the newly selected model.